Микродвигатель-маховик для малого космического аппарата

Выпускная квалификационная работа состоит из 120 с. текстового материала, 41 рисунков, 8 таблиц, 30 источников литературы, 5 листов графического материала. Ключевые слова: малый космический аппарат, системы ориентации и навигации, двигатель-маховик, бесконтактный двигатель постоянного тока, система управления бесконтактными двигателями постоянного тока, микроконтроллер, датчик положения ротора, драйвер, силовые ключи, ПИД-регулятор. Объектом исследования является двигатель-маховик для малого космического аппарата. Цель работы – разработка системы управления двигателем-маховиком для малого космического аппарата, построенным на основе бесконтактного двигателя постоянного тока. В процессе исследования проводились: разработка системы управления двигателем-маховиком при использовании специализиFinal qualifying work includes XX pages of textual material, XX pictures, XX tables, XX references, X graphic sheet material. Keywords: small spacecraft, orientation and navigation system, motor-flywheel, brushless direct current motor, brushless DC motor control system, microcontroller, rotor position sensor, driver, power switch, PID-regulator. The object of research is the motor-flywheel for small spacecraft. Aim of the work – development of the motor-flywheel control system for small spacecraft, built on the basic of brushless DC motor. In the process of research development of the motor-flywheel control system using specialized microchip and microcontroller, development of electric schematic diagram developed system, development of technological process assembly PCA, development of

Polycyclic Aromatic Hydrocarbons (PAHs) in the atmosphere of the Baltic Sea Region

The paper presents a review of publications on the concentrations of polycyclic aromatic hydrocarbons in the atmosphere of the Baltic Sea Region (BSR). It indicates the main emission sources of these substances, related to anthropogenic activity. These include incomplete combustion of fuels in engines on land and from marine transportation, as well as the burning of coal in the community sector. High PAH concentrations in the air are also related to increased industrial activity in urban areas. In the Baltic Sea Region, Germany and Poland have been determined to be responsible for the greatest proportion of PAH emissions. However, the highest number of exceedances of the accepted annual norm for benzo(a)pyrene concentrations was recorded in Poland

The contamination of bottom sediments in the Southern Baltic with polycyclic aromatic hydrocarbons (PAHs)

The study involved a comparative analysis of PAH (polycyclic aromatic hydrocarbons) concentrations in the bottom sediments of the southern part of the Baltic Sea. It was determined that the contamination of sediments with PHAs is considerable (>500 ng/g), with the predominance of pyrogenic PAHs. Polycyclic aromatic hydrocarbons become deposited mainly in anaerobic or extremely anaerobic areas, with a large proportion of the <0.063 mm fraction and a sizeable content of organic matter. In the studied regions, the contamination of sediments was the consequence of anthropogenic activity

Deciphering Plant-Insect-Microorganism Signals for Sustainable Crop Production

Agricultural crop productivity relies on the application of chemical pesticides to reduce pest and pathogen damage. However, chemical pesticides also pose a range of ecological, environmental and economic penalties. This includes the development of pesticide resistance by insect pests and pathogens, rendering pesticides less effective. Alternative sustainable crop protection tools should therefore be considered. Semiochemicals are signalling molecules produced by organisms, including plants, microbes, and animals, which cause behavioural or developmental changes in receiving organisms. Manipulating semiochemicals could provide a more sustainable approach to the management of insect pests and pathogens across crops. Here, we review the role of semiochemicals in the interaction between plants, insects and microbes, including examples of how they have been applied to agricultural systems. We highlight future research priorities to be considered for semiochemicals to be credible alternatives to the application of chemical pesticides

Network flow methods for electoral systems

Researchers in the area of electoral systems have recently turned their attention to network flow techniques with the aim to resolve certain practically relevant problems arising in this area. The aim of this paper is to review some of this work, showing the applicability of these techniques even to problems of a very different nature. Major emphasis will be placed on biproportional apportionment, a problem that frequently arises in proportional electoral systems, but which in some countries is still ill-solved, or not dealt with rigorously, notwithstanding the availability of several sound solution procedures and their concrete application in some real-life elections. Besides biproportional apportionment, we shall discuss applications of network flows to problems such as vote transitions and political districting. Finally, we address the so-called give-up problem, which arises in the current elections for the Italian Parliament. It is related to the possible assignment of seats to multiple winners of a given party. Based on the results and techniques presented in this article, it is fair to state that network flow models and algorithms are indeed very flexible and effective tools for the analysis and the design of contemporary electoral systems. (C) 2011 Wiley Periodicals, Inc. NETWORKS, Vol. 59(1), 73-88 201

Biological aspects of phage therapy versus antibiotics against Salmonella enterica serovar Typhimurium infection of chickens

Phage therapy is a promising alternative treatment of bacterial infections in human and animals. Nevertheless, despite the appearance of many bacterial strains resistant to antibiotics, these drugs still remain important therapeutics used in human and veterinary medicine. Although experimental phage therapy of infections caused by Salmonella enterica was described previously by many groups, those studies focused solely on effects caused by bacteriophages. Here, we compared the use of phage therapy (employing a cocktail composed of two previously isolated and characterized bacteriophages, vB_SenM-2 and vB_Sen-TO17) and antibiotics (enrofloxacin and colistin) in chickens infected experimentally with S. enterica serovar Typhimurium. We found that the efficacies of both types of therapies (i.e. the use of antibiotics and phage cocktail) were high and very similar to one another when the treatment was applied shortly (one day) after the infection. Under these conditions, S. Typhimurium was quickly eliminated from the gastrointestinal tract (GIT), to the amount not detectable by the used methods. However, later treatment (2 or 4 days after detection of S. Typhimurium in chicken feces) with the phage cocktail was significantly less effective. Bacteriophages remained in the GIT for up to 2-3 weeks, and then were absent in feces and cloaca swabs. Interestingly, both phages could be found in various organs of chickens though with a relatively low abundance. No development of resistance of S. Typhimurium to phages or antibiotics was detected during the experiment. Importantly, although antibiotics significantly changed the GIT microbiome of chickens in a long-term manner, analogous changes caused by phages were transient, and the microbiome normalized a few weeks after the treatment. In conclusion, phage therapy against S. Typhimurium infection in chickens appeared as effective as antibiotic therapy (with either enrofloxacin or colistin), and less invasive than the use the antibiotics as fewer changes in the microbiome were observed